Surfacing apparatus



H. R. STRATFORD SURFACING APPARATUS Filed Nov.

Oct. 28, 1930.

I INVLENTOR. #673272 f frafforc/ @i; M? 99mg A TTORNEYS Patented Oct. 28, 1930 UNITED STATES PATENT OFFICE HERBERT R. STRATFORD, OF CLEVELAND, OHIO, ASSIGNOR TO THE STRATMORE COM PANY, OF CLEVELAND, OHIO, A CORPORATION 01 OHIO SUBFAGING APPARATUS Application filed November 16,1928. Serial N'o. 319,821.

The present invention, relating, as indicated, to surfacing apparatus is more particularly directed to an improved supporting pad for use in surfacing apparatus of the type now so commonly used for grinding, polishing, bufiing and similarly treating surfaces such as panels of wood, metal and other material, and such articles as castings, automobile bodies, fenders, hoods and the like. The apparatus commonly employed for this purpose consists of a frame or casing provided with handles for an operator and with a projecting shaft, on the end of which is mounted a supporting pad, against which is removably secured a surfacing disk, usually constructed of abrasive adhesively secured to a suitable backing of paper, cloth or some combination of the two. The shaft on which the pad and disk are carried is operated through gearing journaled in the frame or casing and then by a flexible shaft extending to a suitable source of power, although in many cases the operating shaft which carries the pad and disk are operated directly from a self-contained air or electric motor mounted in the frame or casing.

The present invention is directed to a new and improved pad to be used in machines of the above construction and for the purposes, some of which are referred to above. The principal object of the invention is the provision of a simple and inexpensive pad for the purpose described and one which hasa more universal application and usefulness than the more specialized and expensive pads which have heretofore been employed, but

a which have been better adapted tosome individual type of surfacing operation than to general operations involving a considerable range of operations.

. To the-accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims;

the annexed drawing and the following description setting forth in detail certain mech-n anism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings Fig. '1 is a side elevation partially in section showing my improved pad mounted on a surfacing apparatus of the character described; Flg. 2 is a transverse central section showing a modification of the pad of Fig. 1; Fig. 3 is a similar view showing another modification; and Fig. 4 is a side elevation showing the operation of my improved pad against one typeof surface.

In Fig. 1 I have shown a surfacing apparatus consisting of the frame or casing 1 provided with annularly related handles 2' and 3, of which the handle 3 is hollowand is adapted to receive therein a flexible shaft (not shown)- for the operation of suitable connecting gears (not shown) mounted in a casing 1 and adapted to operate a shaft 4 extendin from the lower side of the casing.

The sha 4 is adapted to removably receive my improved supporting pad, which will now be described.

My improved pad consists of a circular disk 10 of some tough, resistant, compressible and flexible material, such for exam le as rubber, provided with a hub 5 dispbse centrally therein and ada ted to be removably engaged on the threa ed lower end of the shaft 4, The pad is provided with a beveled. edge portion 11 and with a number of la ers of reinforcing material such as strong fa ric 12 embedded in the rearward section of the pad. It is also rovided with a recessed cen- 'tral portion 13, etween which and the lockthe'threaded hollow end of the shaft 4.

The pad shown in Fig. 1 is provided with a central reinforcing section 20 consisting of rubber or similar material integrallyvunited to the forward portion 10 of the pad, there beingseveral layers of the reinforcing material 21 in the lower portion of this supporting section 20. The latter is also so formed as to progressively support the forward section 10 of the pad when under 1 teral pressure, permitting the pad when sever ly pressed out of its normalplane, as for example, when operating under the conditions illustrated in Fig. 4,- to bend through a considerable angle through the portion outside of the supporting section. It will be understood too that some flexibility is permitted at the outer edge of the supporting section, butthis flexibility decreases toward the center of the pad,

thus preventing the entire pad from being unduly flexible and given it a sufiicient rigidity to allow it to cut even when pressed against concave surfaces.

A modification of the construction just described is shown in Fig. 2, in which a pad 30, also formed of the same type of material as already described, is provided with a rearward or reinforcing section 31 integrally united to the forward section 30, the two sections being reinforced through their common portion by layers of tough fabric32. In this form of pad the reinforcing or stiffening effect of the rearward section is of course more pronounced than in the form previously described, since the reinforcing section extends radially from outward; The tapering of the reinforcing section, however, still permits of a considerable flexing of the entire pad through the outer or operating portion of the abrasive disk and permits substantially the same action as with the previous pad, and is illustrated in Fig. 4.

In Fig. 3 I have shown still another modification, in which a pad {10, also formed of the same tough material previously described, is doubly reinforced, first, by a tapered supporting section 31, and, second, by a semirigid reinforcing plate 42, which is secured in a suitable recess in a central hub member 43.

The plate 42 may be formed either of metal, hard rubber, bakelite, or similar material, and

may be provided with a plurality of openings 44- thereth'rough, through which the rubber required and when the machine is applied'to I the surface with heavy pressure.

' Other modes of applying the principle of my invention maybe employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the meansstate'd' by" any of the following claims or-the equivalent of such stated means be employed. j

I therefore particularly point out and distinctly claim as my invention 1. A supporting pad of the character described comprising a circular disk of tough fiexure-resistant compressible material having reinforcing material embedded therein and having an integrally united rearwardly extending portion of smaller area than the disk proper adapted to reinforce and progressively supppg saiddisk against fiexure While permitting exure of its outermost portions.

2. A supporting pad of the character described comprising a circular disk of tough fiexure-resistant compressible material and a tapered annular rearwardly extendin portion of the same material integrally united to' HERBERT R. STRATF'ORD.

or other material of the pad 40 may extend in order to securely and integrally unite the reinforcing plate to the material of the pad proper.

In a pad of the character described intend-i ed for, a number of different operations and for use against different types of surfaces it is essential that the pad operate in as nearly as possible the same manner as relatively stiff pads when used' on flat surfaces. If this action is not secured then thepad, even on flat surfaces, has to be applied to the work with considerable pressure to produce the desired cutting action, causing a considerable flexing and a resultant severe wear on the abrasive disk tending both to break the backing of the disk and to loosen the grain of abrasive therefrom. The present pad is well adapted to the varied service for which it is intended. It has suflicient rigidity to operate on flat surfaces without the use of any considerable pressure and is still sufficiently flexible to follow surfaces of considerable concavity when izs 

